Subversion Repositories mkgmap

/*
 * Copyright (C) 2007 Steve Ratcliffe
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *
 * Author: Steve Ratcliffe
 * Create date: Dec 1, 2007
 */
package uk.me.parabola.mkgmap.build;

import uk.me.parabola.log.Logger;
import uk.me.parabola.mkgmap.filters.FilterConfig;
import uk.me.parabola.mkgmap.filters.MapFilter;
import uk.me.parabola.mkgmap.filters.MapFilterChain;
import uk.me.parabola.mkgmap.general.MapElement;

import java.util.ArrayList;
import java.util.List;

/**
 * This calls all the filters that are applied to an element as it is added to
 * the map at a particular level.
 *
 * @author Steve Ratcliffe
 */
public class LayerFilterChain implements MapFilterChain {
        private static final Logger log = Logger.getLogger(LayerFilterChain.class);
       
        // The filters that will be applied to the element.
        private List<MapFilter> filters = new ArrayList<MapFilter>();

        // The position in the filter list.
        private int position;

        private final FilterConfig config;

        public LayerFilterChain(FilterConfig config) {
                this.config = config;
        }

        public void doFilter(MapElement element) {
                int nfilters = filters.size();

                log.debug("doing filter pos=", position, "out of=", nfilters);
                if (position >= nfilters)
                        return;
               
                MapFilter f = filters.get(position++);
                try {
                        f.doFilter(element, this);
                        // maintain chain position for repeated calls in the split filters
                        position--;
                } catch (RuntimeException e) {
                        position--; // maintain position
                        throw e;
                }
        }

        /**
         * Start the filtering process for an element.
         * @param element The element to add to the map.
         */
        void startFilter(MapElement element) {
                position = 0;
                doFilter(element);
        }

        /**
         * Add a filter to this chain.
         *
         * @param filter Filter to added at the end of the chain.
         */
        public void addFilter(MapFilter filter) {
                assert config != null;

                filter.init(config);
                filters.add(filter);
        }
}